Lack Of Power, Sluggish Or Spongy Symptom - Mercury MerCruiser MCM 454 Mag MPI Service Manual

SERVICE MANUAL NUMBER 23
Surges and/or Chuggles Symptom (Continued)

Lack of Power, Sluggish or Spongy Symptom

Step
Definition: Engine delivers less than expected power. Little or no increase in speed when
throttle lever is advanced part way.
Index
90-861326--1 MARCH 1999
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1. Visually/physically check vacuum
hoses for splits, kinks and proper
connections and routing.
15
2. If a problem is found, repair as
necessary.
Was a problem found?
1. Check or proper alternator voltage
output.
2. The voltage should be between
specified values.
16
3. If a problem is found, repair as
necessary.
Was a problem found?
1. Review all diagnostic procedures
within this table.
2. If all procedures
completed and no malfunctions
have been found, review/inspect the
following:
Visual/physical inspection.
17
Scan tool data.
All electrical connections within a
suspected circuit and/or system.
3. If a problem is found, repair as
necessary.
Was a problem found?
Action
Was the "On-Board Diagnostic" (OBD)
1
System Check performed?
Compare engine performance with a
similar engine. Both should be close.
2
Is engine performance close to similar
engine.
Was visual/physical check performed?
3
1. Remove and check flame arrestor
for dirt, or for being restricted.
4
2. Replace flame arrestor if necessary.
Was a problem found?
1. Check for contaminated fuel.
2. Check water separating fuel filter.
5
3. If a problem is found, repair as
necessary.
Was a problem found?
FUEL INJECTION SYSTEM TROUBLESHOOTING
-
11-16
Volts
have been
-
Value(s)
-
-
-
-
-
Go to OBD
System
Go to Step 16
Check
Go to OBD
System
Go to Step 17
Check
Contact
MerCruiser
Go to OBD
Customer
System
Service
Check
Yes No
Go to OBD
Go to Step 2
System Check
No problem
Go to Step 3
found
Go to Visual/
Physical
Go to Step 4
Check
Go to OBD
System
Go to Step 5
Check
Go to OBD
System
Go to Step 6
Check
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